Rotary piston charger-brake mechanism



D. P. GROVER ROTARY PISTON CHARGER-BRAKE MECHANISM Jan. 23, 19$2 2Sheets-Sheet 1 INVENTOR. 1111111111 E EITDVEI at 4 X} 23134 4.67.

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ROTARY PISTON CHARGER-BRAKE MECHANISM Filed June 24, 1960 2 Sheets-Sheet2 INV EN TOR.

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3,017,807 Patented Jan. 23, 1962 3,017,807 ROTARY PISTON C i GER-BRAKEMECHANISM Donald P. Grover, Chicago, 111., assignor to the United Statesof America as represented by the Secretary of the Army Filed June 24,1960, Ser. No. 38,686 7 Claims. (Cl. 89-12) This invention rel-ates tomachine guns having a rotary mass, such as the machine guns of theGatling-type, and pertains more particularly to devices for starting andbraking the rotation of the rotary mass.

With machine guns of the Gatling-type, the rotary mass, which includes aplurality of caged barrels, must be rotated for operation of the gun bya drive motor. Sometimes the drive motors are energized by an externalsource of power and are either electrically or hydraulically energized.Recently, motors have been introduced which are powered by the pressureof the gases produced during the operation of the gun and which,therefore, require an auxiliary charging device for rotating the rotarymass to fire the first round.

In modern warfare it is important that the machine guns accelerate tooperating speed as soon as possible because the time that the target iswithin range is very limited. The inertia of the rotary mass of theGatlingtype machine guns is considerable as the rotary mass in cludesthe group of caged barrels and, therefore, excessive strain is placedupon the drive mechanisms during acceleration and the motors suitablefor gun use do not provide the desired acceleration.

Moreover, with Gatlingtype machine guns, it is also important that therotary mass, which also drives the firing mechanism, be stopped asquickly as possible after firing is stopped to prevent the passage oflive cartridges through the gun system.

It is, therefore, an object of this invention to provide for a machinegun having a rotary mass, which is rotated during operation thereof,means for assisting the drive motor in accelerating the rotary mass tooperating speed. 7 It is a further object of this invention to providefor such gun auxiliary charging means for rotating the rotary mass tofire the first round when the gun is self-energized.

It is another object of this invention to incorporate into such startingdevice means for braking the rotary mass to a stop.

It is a further object of this invention to provide such a starter-brakedevice which is powered by an oscillatable vane-type piston adapted tostart the rotary mass, when actuated in one direction, and to brake itwhen actuated in the opposite direction.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

FIG. 1 is a side view of a Gatling-type machine gun with thestarter-brake device assembled to the rear end thereof;

FIG. 2 is an enlarged view taken along line 22 of FIG. 1; and

FlG. 3 is a view taken along line 33 of FIG. 2.

Shown in the figures is a machine gun-12 of the Gatlingtype whichincludes a casing 13 with a rotor 14 therein which is part of a rotarymass 15 that also includes a plurality of caged barrels 16. Rotary mass15 rotates in a counterclockwise direction during the operation of gun12 and is driven by motor 17 which is energized by discharge gases afterthe gun begins firing. Mounted to the rear end of casing 13 is astarter-brake device 18 which includes a cylindrical housing 20 and acover 22 which closes the open rear end thereof. A shaft 24 is connectedat the front end to rotor 14 by spline means 25 so as to be rotatablewith the rotor and is journaled at the rear end to cover 22 so as tocoaxially align with the rotor.

Housing 20 is divided into a front-cavity 2'6 and a rearcavity 28, whichare both of cylindrical configuration, by an annular flange 30 which isintegral with the housing and is disposed at right angles to the axis ofshaft 24. Flange 30 forms a hole 31 which is concentric to shaft 24.Mounted on shaft 24 within rear-cavity 28 is an overrun clutch which maybe of any conventional design suitable for performing the functionsnoted hereinafter and which is shown schematically at 32. Clutch 32mounts in turn a vane-type piston 33 having a sleevelike hub 34 whichreceives clutch 32 and an outside periphery 36 which is concentric tothe inside periphery of the surrounding section of housing 20. The frontend of hub 34 has rotating cont-act with the rear face of flange 30while the rear end has rotating contact with the front face of cover 22.

Housing 20 includes a pad 38 which is integral therewith and with flange30 and which extends upwardly into rear-cavity 28. Pad 38 includes anupper end 40, which is concavely formed to matingly contact outsideperiphery 36 of hub 34, and a pair of sides 42 which are disposedradially respective thereto and are spaced apart at an angle of Thus,there is formed in rearcavity 28 an annular chamber 44 which is definedby sides 42, outside periphery 36 of hub 34, the inside periphery ofhousing 20, the rear face of flange 30, and the inside of cover 22.

Piston 33 includes a vane 46 which extends radially from hub 34 foroscillation in chamber 44 between contact with the opposite sides 42.Vane 46 has sliding contact with the inside periphery of housing 20, therear face of flange 30 and the inside of cover 22. The contactingsurfaces of vane 46 and chamber 44 are polished and suitable seals 45are provided thereat to make air tight contact therebetween. Suitableseal are also provided between the contacting areas of hub 34, cover 22and flange 30 as well as between the contacting surfaces of pad 38 andthe hub and between vane 46 and housing 20 so that chamber 44 is airtight.

A bore 48 extends through pad 38 to communicate with chamber 44 at eachof the sides 42 and each of the bores is provided wit-h a coupling 50which is connected by tubing means to a gas pressure source 52. Asuitable valve 54 is interposed between source 52 and starterbrakedevice 18 to provide means for directing air pres sure from such sourceto either side 'of vane 46 for selectively oscillating piston 33 in acounterclockwise starting direction or a clockwise braking direction.Clutch 32 is designed to transfer the rotation of piston 33 in thestarting direction to shaft 24, and permit the shaft to overrun thepiston when the speed of the shaft exceeds that of the piston, and topermit free rotation of the piston relative to the shaft when the pistonis rotated in the braking direction. As sides '42 are spaced at an angleof 120, vane 46 is oscillatable through an angle of 240 which issufiicient to pass several of the barrels 16 through the firing positionof gun 12 for discharge of the cartridges therein to provide the powerfor energizing motor 17 and, in cooperation with motor 17, acceleraterotary mass 15 to operating speed.

Mounted in front-cavity 26 is a multiple-disc, braking device 56 whichis installable therein by housing 20 being separable, as noted at 58, atsuch front-cavity. Braking device 56 includes a plurality offriction-faced plates 60 with pressure discs 62 disposed therebetweenand in front of the first and in back of the rear plate. Plates 60' areconnected by spline means 63 to an increased diameter portion 64 onshaft 24 so as to be displaceable longitudinally therealong while beingrestrained from rotation relative thereto. Discs 62 are similarlyconnected by spline means 65 to a collar insert 66 which is anchored tohousing 20 at joint 58. The front one of the discs 62 contacts the frontend of housing 20 so as to be blocked thereby from a forwarddisplacement while the rear one of the discs is displaceable by acamdevice 68 to squeeze the plates 60 and discs 62. together and therebytransfer the energy in rotary mass 15 to housing 20.

Cam device 68 includes a cam plate 70 which is slidingly disposed onshaft 24 in front-cavity 26. Cooper-ating cam surfaces 72 are providedon the adjacent faces of hub 34 and cam plate 70, which cam surfaces aredisposed between the inner periphery of flange 30* and the exterior ofshaft 24 and are formed to transfer rotation of piston 33 in the brakingdirection to forward displacement of cam plate 70 against braking device56 for stopping the rotation of shaft 24 and thereby the rotation ofrotary mass 15. Conversely, cam surfaces 72 release braking device 56during rotation of piston 33 in the starting direction. A Bellville-typespring 74 is interposed between cam plate 70 and the rear one of thediscs 62 to provide a smooth braking action when piston 33 is actuatedin the braking direction.

Thus, when gun 12 is inoperative, piston 33, through the previousactuation thereof to brake the gun, is positioned so that vane 46 is incontact With the right one of the sides 42-. When gun 12 is started toinitiate a burst, valve 54 -is simultaneously actuated through aconnection with the gun firing mechanism (not shown) to opencommunication between gas pressure source 52 and the right one of thebores 48. Whereby, gas pressure enters chamber 44 to act upon vane 46and thereby rotates piston 33 in the counterclockwise starting directionuntil stopped by contact of the vane with the left one of the sides 42.The rotation of piston 33 is transferred through clutch 32 to shaft 24for rotation of rotor 14 and thereby pass the succeeding barrels 16through the firing position for the discharge of the cartridges in suchbarrels. Whereby, motor 17 is energized to continue the rotation ofrotary mass 15 with the pressure of the gases against piston 33assisting the motor in accelerating rotary mass 15 to operating speed.

When the firing of gun 12 is stopped, the release of the firingmechanism thereof actuates valve 54 to open communication between gaspressure 52 and the left one of the bores 48. Whereby, piston 33 isrotated in the clockwise braking direction and such rotation isconverted to longitudinal actuation of braking device 56 to stop therotation of rotary mass 15 and thereby prevent an overrun which wouldpass live cartridges through gun 12.

From the foregoing it is clearly apparent that there is provided hereina compact, rugged 'and simply operated starter-brake device whichassists the drive motor of a machine gun in starting the rotation of therotary mass thereof and accelerate the rotary mass to operating speedand which brakes the rotary mass at the end of a burst to prevent thepassage of live cartridges through the gun system.

Although a particular embodiment of the invention has been described indetail herein, it is evident that many variations may be devised withinthe spirit and scope thereof and the following claims are intended toinclude such variations.

I claim:

1. In a machine gun having a rotary mass with a rotor contained within acasing, a starter-brake device comprising a cylindrical housing mountedto the rear end of the casing, an annular flange disposed within saidhousing integral with the inside periphery thereof for forming afront-cavity, a rear-cavity and a hole to provide communicationtherebetween, a cover for closing the rear end of said housing, a shaftjournaled in said cover and connected to the rotor for rotation in axialalignment therewith, a piston mounted over said shaft in saidrear-cavity, a clutch disposed between said shaft and piston to mountsaid piston for oscillating rotation, said clutch being adapted totransfer movement of said piston in the direction of operation of saidrotor to said shaft while permitting free movement of said pistonrelative to said shaft when moved in the opposite braking direction, amultidisc friction brake disposed in said front-cavity for releasablyengaging said shaft to said housing to stop the rotation of the rotarymass, and cam means interposed between said piston and said shaft insaid hole formed by said flange for converting rotation of said pistoncounter to the direction of rotation of the rotor to actuation of saidbrake.

2. The gun as defined in claim 1 wherein said piston includes a hollowhub for receiving said clutch to mount said piston for oscillatingrotary movement around said shaft and a vane extending radially fromsaid hub, and wherein a pad extends upwardly into said rearcavityintegral with said housing and flange, said pad being provided with anupper end having contact with said hub and angularly disposed sides forcontactingly limiting the oscillation of said piston, and wherein saidvane is slidingly disposed in an annular chamber formed by the insideperiphery of said housing, the outside periphery of said hub, the rearface of said flange, the inside of said cover and said sides of saidpad.

3. In a machine gun having a rotary mass energizable by a motor, apiston disposed in an accommodating chamber for intermittentdisplacement in alternate directions, a brake device disposed forstopping the rotation of said rotary mass, at first means fortransferring displacement of said piston in one of the alternatedirections to the rotary mass to cooperate with the motor inaccelerating the rotary mass to operating speed and a second means fortransferring displacement of said piston in the opposite one of thealternate directions to said brake device for stopping the rotary mass.

4. The gun as defined in claim 3, wherein said chamber is of annularconfiguration and wherein said piston is of oscillating rotary type andincludes a hub with a radially extending vane accommodated for pivotalmovement within a limited arc in said chamber.

5. The gun as defined in claim 3, wherein said first means includes anoverrun type of clutch whereby the rotation of said piston in one of thealternate directions is transferred to the rotary mass and whereby therotary mass is permitted to overrun said piston when the movement ofsaid piston is suspended.

6. The gun as defined in claim 3, wherein said second means includes apair of cam surfaces interposed between said piston and said brakedevice for converting rotation of said piston to linear displacement ofsaid brake device.

7. In a machine gun having a rotary mass energizable by a motor, astarter-brake device including a fluid actuated vane-type pistondisposed for oscillation in a limited arc in an annular chamber, a brakedevice actuatable to stop the rotation of the rotary mass, a clutchoperationally disposed between said piston and the rotary mass fortransferring rotation of said piston in one direction thereto, and cammeans operationally disposed between said piston and said brake devicefor actuation thereof to stop the rotary mass when said piston isrotated in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS520,185 Gatling July 25, 1893 2,756,639 Bird July 31, 1956 2,767,615Hardy Oct. 23, 1956

